Process of making piano string



Jan. 24,1961 R. E. JOHNSON 2,968,863

PROCESS OF MAKING PIANO STRING Original Filed March 18. 1953 IN V EN TOR. ffoberzfJo/zrzafl;

United States Fate PROCESS OF MAKING PIANO STRING Robert E. Johnson, 2011 Clybourn Ave., Chicago, 111.

Original application Mar. 18, 1953, Ser. No. 343,196,

now Patent No. 2,746,335, dated May 22, 1956. Divided and this application Jan. 6, 1956, Ser. No. 557,795

4 Claims. (Cl. 29-1695) This invention relates to a process of forming a piano string having a covering wire wound tightly thereon and more particularly, to a process of forming a piano string of such character which incorporates as one step thereof the distorting of a plurality of turns on at least one end of the covering wire by swaging or the like in order to form a tapered, gripping end on the covering wire.

This application is a division of applicants copending application, Serial Number 343,196, filed March 18, 1953, entitled Piano String, now Patent No. 2,746,335, issued on May 22, 1956.

When the conventional process of manufacturing by hand piano strings having a covering wire wound on a core wire is utilized, one end of the covering wire is not firmly secured to the core wire. Such' a condition will very often result in rattles and buzzes in the piano string after it has been installed, since the end of the covering wire is likely to vibrate independently of the core wire.

In the improved method of winding a piano string of the character described, which is the subject of this invention, the end of the core wire adjacent the hitch-pin end of the wire is firmly secured to the core wire. This end of the covering wire is pressed into the core wire by a suitable tool, and at the same time, the core wire and covering wire are rotated. This results in this end of the covering wire being firmly seated on the core wire. However, in this conventional, manual method of winding, the opposite end of the covering wire (adjacent the tuning pin end) is not firmly secured in this manner, but is merely left in the position it assumes after the excess covering wire is separated therefrom by a quick bending or a breaking motion. This breaking movement of the covering wire has a tendency to raise the last few turns of the covering wire slightly so that they are not in firm contact with the core wire. This method of removing the excess covering wire not only has a tendency to produce the undesirable results described after installation of the wire, but also is very likely to leave rough or sharp projections at this end of the piano string. These, in turn, may cause abrasions or cuts on the hands of an individual installing such a string. Likewise, such a condition detracts from the appearance of the string.

It is therefore an object of this invention to provide an improved method for producing a piano string, which string has a covering wire thereon terminating in a taper at at least one end.

I Another object is to provide an improved method for making a piano wire of the character described in which a plurality of turns in at least one end of the covering wire are distorted by causing the material therein to flow so that a tightly gripping end is formed in the covering wire.

Yet another object of this invention is to provide an improved process of making a piano wire which produces a wire having no rough or sharp projections at the ends of the covering wire which may cause injury to the hands it an individual handling such a wire.

Another object is to provide an improved method of producing a piano string of the character described which has a greatly improved and finished appearance.

Still another object of this invention is to provide a new and improved process of forming a piano string of the character described which includes a step of causing the material in a plurality of turns at one end of the covering wire to flow so that a tapered end is formed in the covering wire.

Further objects and advantages of this invention will become evident as the description proceeds and from an examination of the accompanying drawing which illustrates one embodiment of the invention and in which similar numerals refer to similar parts throughout the several views.

In the drawing:

Figure 1 is a view in elevation of one form of piano string embodying the invention;

Figure 2 is an enlarged fragmentary view of a portion of the piano string shown in Figure 1 showing in greater detail one end of the covering wire; and

Figure 3 is an enlarged fragmentary view in vertical cross section of the same portion of the piano string shown in Figure 2.

Referring now to Figure 1, one form of piano string embodying the invention is shown therein, indicated generally by the numeral 10. The complete piano wire 10 is made of a core wire 12, an undercovering wire 14,- and a covering wire 16. The undercovering wire is in the form of a winding disposed on the core wire and the covering wire is in the form of a winding disposed on top of the undercovering wire and extending slightly beyond onto the core wire 12, at each end. One end of the core. wire 12 has a loop 18 formed therein, this end of the wire 10 being generally known as the hitch-pinyend; The opposite end 20 of the core wire preferably terminates as a straight extension of the core wire 12 and is generally known as the tuning pin end.

In the conventional winding process, the loop 18 is formed in the core wire and the latter is then inserted in a suitable winding machine capable of rapidly rotating the core wire. The undercover-ing wire 14 is then wound on the core wire 12 by first looping the end thereof; through the loop 18 of the core wire and then rapidly rotating the core wire so as to wind the undercovering wire 14 tightly thereon, beginning at a suitable point in spaced relation to the loop 18.

After the unde-rcovering wire 14 is so wound on the core wire 12, the excess wire at the ends can be removed by cutting or breaking away the unwound portions. A covering wire 16 is then applied in substantially the same fashion so that it is wound throughout its length, except at its end, over the undercovering wire 14, as best shown in Figures 2 and 3. A shoulder 22 is formed at the point where the covering wire extends beyond the undercovering wire.

The end of the covering wire which is adjacent the loop 18 in the core wire 12 and is indicated generally, by the numeral 24 normally may have the unwound excess removed therefrom by the use of a suitable cutting numeral 26, however, the separation of the excess from the wound portion is normally accomplished by a quick bending or breaking movement of the wire, as previously mentioned.

ln its preferred form, the process, which is the subject of this invention, incorporates the step of causing the metal in a plurality of turns at the end of the covering wire 16 to flow to form a taperedend on the covering wire. end. turns 28 of the covering wire can best be carried out by a swaging operation, although any method which will produce such a flow can, of course, be utilized. Since the tuning pin end 20 of the piano string, shown in Figure l, terminates in a straight-length of core wire, it is possible to use a rotary swaging machine to produce the desired distortion of the end turns of the cover ing wire. Such a rotary swaging machine may be of conventional form employing a plurality of segmental dies which, when assembled, form a substantially conical die, the individual segments of which may be separately struck. in one form of such a device, these individual segmental dies are activated by rapidly rotating mem' hers which cause a sharp'blow to be strucksuecessively by the segmental dieson the work piece so that a plurality of successive blows are struck around the circumference thereof. 7

Upon insertion of the tuning pin end 20 of the piano string into such a rotary swaging machine in operation,

and upon the application of a small amount of longitudinal pressure to the string in the direction of the machine, the end turns of the covering wire are caused to flow into substantially the form best shown in Figures 2 and 3.

The consecutive activation of the individual dies,-

around the circumference of the complete die assembly, as previously described, should be made to coincide with the direction of the turns of the covering wire; This isdesirable since when a rotary swaging machine of the character described is utilized there is a slight directional character to the impact of each individual die with a resultant tightening or loosening of the individual turns. Obviously, it is desirable to have the impacts directed in such a fashion that they will tend to further tighten the card turns 28 of the" covering wire ratherthan to loosen t em.

The primary result of this swaging processis therefore to cause the metal end turns of the covering winding 16 to flow in such a way that the individual turns are widened and compressed into the form of a conical taper. In other words, each turn is flattened an increased amount toward the end of the winding until the outer extremity of the last turn 30 is only slightly larger in diameter than the core wire itself. This flattening of the end turns therefore actually also elongates the end of the covering wire winding.

Obviously, a conical taper will normally be formed when using a rotary swaging machine of the character described, but the invention is not meant to be limited to a piano wire having this conical form of end on the covering wire, or to a process for forming only this type of wire. Likewise, suitable means other than a rotary swaging machine can, of course, be used to accomplish the distortion described of the end turns of the covering wire. For example, the material in the end turns of the covering wire could be caused to flow by pressing or rolling, as well as by hammering, and conceivably other means of applying force to distort the turns might be devised. The primary purpose of the distortion of the end turns is, of course, to tightly compress the end turns 28 of the covering wire 16 against the core wire 12 regard less of the exact form, imparted to these turns.

To aid in securing the end turns of the covering wire 16 to the core wire 12, it has been found desirable to slightly flatten the portion of the core wire which is associated therewith. For example, the flattening of the core wire at the point 32 provides a means for insuring that the end turn 24 does not slip circumferentially on the core wire 12. A similar flattening of the core Wire under the end turns 28 of the covering wire at flie tuning pin end is also desirable and accomplishes the same result.

The end result ofthe utilization of the process described This'flowing, or distortion, of the metal in these above is the formation of a piano string in which'at least turns of the covering Wire adjacent the end without removing any of the material making up such turns, but merely causing them to flow into a tightly formed, tapered end which grips the core wire securely and positively.

Although the flowing in the manner described of the turns at only one end of the covering wire has been described, obviously the same sort of distortion could be carried out with respect to the turns at the opposite end of the covering wire, the necessity for such modification at the hitch-pin end of the string, however, is not normally so great because of the difference in manufacturing technique. I

In the drawing and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes ering wire on said core wire and securing at least one end of said covering wire to said core wire by applying along an end length of said tightly wound covering wire forming a plurality of contiguous turns, forces increasing progressively in pressure to the end thereof to cause the material in said plurality of turns to flow in directions toward said end and to thereby conform said covering wire to said core wire and form a tapered end on said covering wire.

2. The process of forming a piano string which comprises winding a covering wire on a core wire to form a plurality of tightly wound, contiguous turns of said covering wire on said core wire and securing at least one end of said covering wire to said core wire by repeatedly applying suflicient compressive force at a plurality of consecutive points around the circumference of a plurality of turns of said covering wire adjacent one end thereof to cause the material in said plurality of turns to flow and to thereby conform to said core wire and form a tapered end on said covering wire, said consecutive points being in a path extending in the same direction as the direction of winding of said turns of said covering wire.

3. The process of forming a piano string which comprises windinga covering wire on a core wire to form a plurality of tightly wound, contiguous turns of said covering wire on said core wire and securing at least one end of said covering wire to said core wire by repeatedly striking a plurality of said turns adjacent at least one end of said covering wire with a plurality of swages disposed radially about said core wire and causing the metal in said plurality of turns to flow so as to conform to said core wire and form a tapered end on said winding.

4. The process of forming a piano string which comprises winding a covering wire on a core wire to form aplurality of tightly wound, contiguous turns of said covering wire on said core wire and securing at least one end of said covering wire to said core wire by repeatedly striking a plurality of said turns adjacent at least one end of said covering wire at a plurality of consecutive points around the circumference of said turns with a plurality of swages disposed radially about said core wire and cansing the metal in said plurality of turns to flow so as to conform to the surface of said core-wire and form a tightened tapered end on said winding, said consecutive points being in a path extending in the same direction as the direction of windingof said turns of said ebvering 2,759,166 wire. 2,766,983

References Cited in the file of this patent UNITED STATES PATENTS 5 593 066 2,262,802 Hayden Nov. 18, 1941 3881468 2,683,207 Lewis et a1 July 6, 1954 6 Mallina Aug. 14, 1956 Taylor Oct. 16, 1956 FOREIGN PATENTS France Aug. 17, 1925 Great Britain Mar. 2, 1933 

